Feasibility of amifostine administration in conjunction with high-dose rate brachytherapy.

This ongoing study was initiated to determine the feasibility of administering amifostine (Ethyol, WR-2721; MedImmune, Inc, Gaithersburg, MD) with monomodal high-dose rate (mHDR) brachytherapy and to assess the tolerability and side effects of this combination. To date, 18 patients suitable for prostate implant brachytherapy (<or=T2aN0; prostate-specific antigen <or= 10 ng/mL; Gleason score <or= 6) have been treated with mHDR brachytherapy, receiving four 9-Gy fractions administered twice daily for 2 days. Amifostine (500 mg) is administered subcutaneously on the day before implant and 30 to 60 minutes before the first and third mHDR treatments. All 18 patients have received amifostine and brachytherapy as planned. Nausea was manageable with oral prochlorperazine in the pretreatment phase and our standard antiemesis protocol (intravenous promethazine, with granisetron if needed) during the implant; hypotension and asthenia were not problematic. During the 2-week post-treatment phase, grade 1 cystitis occurred in eight of 18 patients; grades 1 and 2 proctitis occurred in six of 18 and five of 18 patients, respectively. Six patients developed urinary obstruction symptoms. Preliminary results support the feasibility and tolerability of subcutaneous amifostine in conjunction with mHDR brachytherapy. Total accrual goal is 50 patients to assess long-term efficacy. Additional studies of HDR with amifostine are planned for patients with recurrent prostate and gynecologic cancer.